1. Field of the Invention
The present invention relates to an elevator having a plurality of cars within one hoistway, and particularly to a power supplying device for a plural car elevator, the power supplying device supplying electricity to each of the cars.
2. Description of the Related Art
An elevator car is provided with electrical appliances such as lighting equipment, a ventilator, and an air-conditioner, and these electrical appliances need to be supplied with power.
FIG. 7 is a perspective view showing a power supplying device for an elevator which is now widely used. FIG. 8 is a transverse sectional view corresponding to FIG. 7.
This power supplying device for an elevator comprises a fixed-side power supplying member 3 (including a signal transmission function) disposed at the top of a hoistway 100; a power receiving member 5 disposed on a car 1 traveling within the hoistway 100 along guide rails 2, and a cable 4 for supplying power, the cables being lowered from the fixed-side power supplying member 3 toward the car 1, being fixed on the bottom surface of the car 1 via a upwardly-folded portion 80, and being electrically connected with the power receiving member 5.
The fixed-side power supplying member 3 is disposed in a machine house together with a winding machine driving the car 1, a control member, power source equipment, and the like, and transmits power or signals to the car 1 through the cable 4. Here, reference numeral 50 denotes a counter.
Since the folded portion 80 of the cable 4 is subjected to repeated deformations by successive up and down movements for a long time period (for example, 20 years), it requires a curvature to some extent in order to withstand the repeated deformations. Therefore, to pass through the narrow gap between the car 1 and the wall 101 of the hoistway 100, and to secure a curvature to some extent, the cable 4 is generally fixed on the bottom of the car 1.
However, as shown in FIG. 9 and FIG. 10A, when applying this system to a plural car elevator having first and second cars 1a and 1b within one hoistway 100, a problem arises that, once the cars 1a and 1b approach each other, the folded portion 80a of the first cable 4a of the first car 1a can make contact with the upper portion of the second car, so that the folded portion 80a can be caught on the second car 1b, resulting in a reduction in the lifetime.
As one solution to this problem, there is a suggestion that, as shown in FIG. 10B, for example, the installation positions of the first and second cables 4a and 4b are set to the sides of the first and second cars 1a and 1b, respectively. In this case, however, in order to obtain a bending curvature required for each of the cables 4a and 4b, it is necessary to secure a large space between the cars 1a and 1b, and the wall 101 of the hoistway 100. This also creates a problem that the cross sectional area of the hoistway 100 increases, leading to a reduction in space efficiency.
FIGS. 11A and 11B show the power supplying device for an elevator disclosed in Japanese Unexamined Patent Application Publication No. 9-56088.
This power supplying device for an elevator comprises a fixed-side power supplying member 3 disposed at the top of a hoistway 100; an inverter power supplying member 10 connected to the fixed-side power supplying member 3; a power feeding line 11 disposed along the travel path in the hoistway 100 from the inverter power supplying member 10; a power receiving member 5 disposed on a car 1 traveling within the hoistway 100; a pickup 12 comprising a high-frequency transformer which supplies power to the power receiving member 5 by electromagnetic induction, while being brought close to the power feeding line 11 in a noncontact state; a battery 13 disposed between the pickup 12 and the power receiving member 5.
FIG. 12 is a control block diagram of the power supplying device for an elevator, having the above-described features.
The power supplying device for an elevator comprises a inverter power supplying member 10, a power feeding line 11 connected to the inverter power supplying member 10, a pickup 12 approaching the power feeding line 11 in a noncontact state, and a power receiving member 5 electrically connected with the pickup 12.
The power receiving member 5 comprises a rectifying circuit 31 for rectifying the outputs received by the pickup 12, a stabilization circuit 32 for stabilizing the rectified outputs, a smoothing circuit 33 for smoothing the stabilized outputs, and a control circuit 34 for exercising various controls by the smoothed outputs.
As shown in FIG. 13A, the inverter power supplying member 10 has a DC driving circuit 40, and a switching circuit 41 for converting the DC voltage of the DC driving circuit 40 into AC voltage. The inverter power supplying member 10 outputs the AC voltage converted by the switching circuit 41 to the power feeding line 11.
Meanwhile, no example has been found in which the above-described pickup 12 is applied to a plural car elevator. As shown in FIG. 13B, however, a construction is suggested in which the first and second pickups 12a and 12b of the respective plural cars 1a and 1b enter in series in the power feeding line 11.
In a plural car elevator, one of the cars may be out of operation, and a cooler is turned on or turned off depending on a car, or the like. That is, there are variations in the load between cars. In this case, since the first and second pickups 12a and 12b enter in series in the power feeding line 11, and the voltage is divided between the pickups 12a and 12b, the load causes a fluctuation in of one of the cars 1a fluctuates the voltage applied to the other car 1b. Also, in each of the cars 1a and 1b, the current flowing through the power feeding line 11 fluctuates in accordance with the load fluctuation.
Thus the power supplied to each of the cars 1a and 1b via the first and second pickups 12a and 12b is not stable.
As described above, in the power supplying device for a plural car elevator, having the above-described features shown in FIG. 9, when supplying power to the cars 1a and 1b using the cables 4a and 4b, there is a problem that, once the car 1a and 1b approach each other, the folded portion 80a of the first cable 4a of the first car 1a can make contact with the upper portion of the second car, so that the folded portion 80a of the first car can be caught on the second car, resulting in a reduction in the lifetime. Furthermore, for example, in order to obtain a bending curvature required for the cables 4a and 4b, it is necessary to secure a large space between the cars 1a and 1b, and the wall 101 of the hoistway 100. This also raises a problem that the cross sectional area of the hoistway 100 increases, leading to a reduction in the space efficiency.
Moreover, when supplying power to plural car by the noncontact system using the pickups 12a and 12b, there is a problem that under the influence of the fluctuation of the power supply load to one of the cars, the amount of the power applied to the other car 1b fluctuates, thereby making it difficult to stably supply power to each of the cars.